The Research Methods Core directed by Dr. Thomas Ten Have: 1) provides consultative and educational support to investigators and trainees of the ACISR; 2) develops and refines interventions with efficacy and high likelihood of adoption and patient acceptance; and 3) develops innovative research methods and designs. The core is structured in terms of four interactive standing groups and varying numbers of ad hoc working groups. The four standing groups are the Intervention Development Group (Drs. James Coyne and David Oslin, Co-Directors), the Research Design Group (Dr. Thomas Ten Have, Director), the Assessment Development Group (Dr. Joseph Gallo, Director), and the Qualitative Research Development Group (Dr. Frances Barg, Director). Each group provides sophisticated methodological expertise in conjunction with the Research Support Units of the Operations Core for the conceptualization, design, implementation, analysis, and interpretation of research relevant to the goals of the ACISR. The groups work with investigators to identify and resolve methodological problems that limit the conduct of rigorous, high impact research addressing late-life depression and psychiatric-medical comorbidity as public health problems. This work has already progressed to the four pilot projects described in the Principal Research Core and a number of current and pending R01's, R21's, and other pilot and piggy-back studies. The groups also prepare junior investigators to apply alternative methods, designs and analytic strategies independently. Three ad hoc working groups are currently active: Caregiver Involvement in Depression Management, Benzodiazepine Withdrawal, and History of Depression as a Means of Risk Stratification in Depression Management. Working groups are expected to progress to pilot projects or directly to R21, R01, collaborative Small Business Technology Transfer or Small Business Innovation Research initiatives.